Unify internal and external typed arrays a bit

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/hydrogen.h"
 
 #include <sstream>
 
 #include "src/v8.h"
 
@@ skipping 3149 matching lines @@
 HValue* HGraphBuilder::BuildArrayBufferViewFieldAccessor(HValue* object,
                                                          HValue* checked_object,
                                                          FieldIndex index) {
   NoObservableSideEffectsScope scope(this);
   HObjectAccess access = HObjectAccess::ForObservableJSObjectOffset(
       index.offset(), Representation::Tagged());
   HInstruction* buffer = Add<HLoadNamedField>(
       object, checked_object, HObjectAccess::ForJSArrayBufferViewBuffer());
   HInstruction* field = Add<HLoadNamedField>(object, checked_object, access);
 
-  IfBuilder if_has_buffer(this);
-  HValue* has_buffer = if_has_buffer.IfNot<HIsSmiAndBranch>(buffer);
-  if_has_buffer.Then();
-  {
-    HInstruction* flags = Add<HLoadNamedField>(
-        buffer, has_buffer, HObjectAccess::ForJSArrayBufferBitField());
-    HValue* was_neutered_mask =
-        Add<HConstant>(1 << JSArrayBuffer::WasNeutered::kShift);
-    HValue* was_neutered_test =
-        AddUncasted<HBitwise>(Token::BIT_AND, flags, was_neutered_mask);
+  HInstruction* flags = Add<HLoadNamedField>(
+      buffer, nullptr, HObjectAccess::ForJSArrayBufferBitField());
+  HValue* was_neutered_mask =
+      Add<HConstant>(1 << JSArrayBuffer::WasNeutered::kShift);
+  HValue* was_neutered_test =
+      AddUncasted<HBitwise>(Token::BIT_AND, flags, was_neutered_mask);
 
-    IfBuilder if_was_neutered(this);
-    if_was_neutered.If<HCompareNumericAndBranch>(
-        was_neutered_test, graph()->GetConstant0(), Token::NE);
-    if_was_neutered.Then();
-    Push(graph()->GetConstant0());
-    if_was_neutered.Else();
-    Push(field);
-    if_was_neutered.End();
-  }
-  if_has_buffer.Else();
+  IfBuilder if_was_neutered(this);
+  if_was_neutered.If<HCompareNumericAndBranch>(
+      was_neutered_test, graph()->GetConstant0(), Token::NE);
+  if_was_neutered.Then();
+  Push(graph()->GetConstant0());
+  if_was_neutered.Else();
   Push(field);
-  if_has_buffer.End();
+  if_was_neutered.End();
 
   return Pop();
 }
 
 
 HGraphBuilder::JSArrayBuilder::JSArrayBuilder(HGraphBuilder* builder,
     ElementsKind kind,
     HValue* allocation_site_payload,
     HValue* constructor_function,
     AllocationSiteOverrideMode override_mode) :
@@ skipping 6492 matching lines @@
     // argument to the construct call.
     if (TryHandleArrayCallNew(expr, function)) return;
 
     HInstruction* call =
         PreProcessCall(New<HCallNew>(function, argument_count));
     return ast_context()->ReturnInstruction(call, expr->id());
   }
 }
 
 
+HValue* HGraphBuilder::BuildAllocateEmptyArrayBuffer(HValue* byte_length) {
+  HAllocate* result =
+      BuildAllocate(Add<HConstant>(JSArrayBuffer::kSizeWithInternalFields),
+                    HType::JSObject(), JS_ARRAY_BUFFER_TYPE, HAllocationMode());
+  result->MakePrefillWithFiller();

[Hannes Payer (out of office), 2015/04/30 10:50:18]

Make prefill with filler is not the right thing here. It will preinitialize the
whole space with one word fillers. You are going to overwrite most of them right
after that. Please initialize all fields with sane values.

+
+  HValue* global_object = Add<HLoadNamedField>(
+      context(), nullptr,
+      HObjectAccess::ForContextSlot(Context::GLOBAL_OBJECT_INDEX));
+  HValue* native_context = Add<HLoadNamedField>(
+      global_object, nullptr, HObjectAccess::ForGlobalObjectNativeContext());
+  Add<HStoreNamedField>(
+      result, HObjectAccess::ForMap(),
+      Add<HLoadNamedField>(
+          native_context, nullptr,
+          HObjectAccess::ForContextSlot(Context::ARRAY_BUFFER_MAP_INDEX)));
+
+  Add<HStoreNamedField>(result, HObjectAccess::ForJSArrayBufferBackingStore(),
+                        Add<HConstant>(ExternalReference()));
+  Add<HStoreNamedField>(result, HObjectAccess::ForJSArrayBufferByteLength(),
+                        byte_length);
+  Add<HStoreNamedField>(result, HObjectAccess::ForJSArrayBufferBitFieldSlot(),
+                        graph()->GetConstant0());
+  Add<HStoreNamedField>(
+      result, HObjectAccess::ForJSArrayBufferBitField(),
+      Add<HConstant>((1 << JSArrayBuffer::IsExternal::kShift) |
+                     (1 << JSArrayBuffer::IsNeuterable::kShift)));
+
+  return result;
+}
+
+
 template <class ViewClass>
 void HGraphBuilder::BuildArrayBufferViewInitialization(
     HValue* obj,
     HValue* buffer,
     HValue* byte_offset,
     HValue* byte_length) {
 
   for (int offset = ViewClass::kSize;
        offset < ViewClass::kSizeWithInternalFields;
        offset += kPointerSize) {
     Add<HStoreNamedField>(obj,
         HObjectAccess::ForObservableJSObjectOffset(offset),
         graph()->GetConstant0());
   }
 
   Add<HStoreNamedField>(
       obj,
       HObjectAccess::ForJSArrayBufferViewByteOffset(),
       byte_offset);
   Add<HStoreNamedField>(
       obj,
       HObjectAccess::ForJSArrayBufferViewByteLength(),
       byte_length);
-
-  if (buffer != NULL) {
-    Add<HStoreNamedField>(
-        obj,
-        HObjectAccess::ForJSArrayBufferViewBuffer(), buffer);
-  } else {
-    Add<HStoreNamedField>(
-        obj,
-        HObjectAccess::ForJSArrayBufferViewBuffer(),
-        Add<HConstant>(static_cast<int32_t>(0)));
-  }
+  Add<HStoreNamedField>(obj, HObjectAccess::ForJSArrayBufferViewBuffer(),
+                        buffer);
 }
 
 
 void HOptimizedGraphBuilder::GenerateDataViewInitialize(
     CallRuntime* expr) {
   ZoneList<Expression*>* arguments = expr->arguments();
 
   DCHECK(arguments->length()== 4);
   CHECK_ALIVE(VisitForValue(arguments->at(0)));
   HValue* obj = Pop();
@@ skipping 201 matching lines @@
   ElementsKind fixed_elements_kind =  // Bogus initialization.
       INT8_ELEMENTS;
   Runtime::ArrayIdToTypeAndSize(array_id,
       &array_type,
       &external_elements_kind,
       &fixed_elements_kind,
       &element_size);
 
 
   { //  byte_offset is Smi.
-    BuildArrayBufferViewInitialization<JSTypedArray>(
-        obj, buffer, byte_offset, byte_length);
+    HValue* allocated_buffer = buffer;
+    if (buffer == NULL) {
+      allocated_buffer = BuildAllocateEmptyArrayBuffer(byte_length);
+    }
+    BuildArrayBufferViewInitialization<JSTypedArray>(obj, allocated_buffer,
+                                                     byte_offset, byte_length);
 
 
     HInstruction* length = AddUncasted<HDiv>(byte_length,
         Add<HConstant>(static_cast<int32_t>(element_size)));
 
     Add<HStoreNamedField>(obj,
         HObjectAccess::ForJSTypedArrayLength(),
         length);
 
     HValue* elements;
@@ skipping 3134 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal